Neutrinos travel faster than light! The science world is agog at this unexpected announcement from CERN in Switzerland. This result has to be verified, for if true it seems that one of science’s central tenets is wrong!

An eerie, nearly mirror-image pair of loops of red luminescent gas frame the expanding debris of a star seen as a supernova explosion in 1987. Neutrinos emitted by this explosion did not travel faster than light. (Image Credit: Dr. Christopher Burrows, ESA/STScI and NASA)

It’s all Einstein’s fault of course. Albert Einstein (1879-1955) came up with the theory of relativity that established the speed of light as the cosmic speed limit. Actually Einstein had two theories of relativity, it is the earlier one, ‘special relativity’ published in 1905 under the snappy title “On the electrodynamics of moving bodies”, that lays down the problems with faster than light (FTL) movement. Some of the implications of Einsteinian relativity may seem crazy, for example the idea that time slows down around bodies approaching the speed of light, but this seems to be how the Universe works. Remember, reality has been around since long before we showed up. Experiments have proven relativity’s predictions. Atomic clocks flown around the world on jet planes have been found on landing to have run slightly slower than identical clocks ticking away back home in the lab.

So what are neutrinos? Neutrinos are strange ghostly little particles; they have an extraordinary ability to pass straight through matter. It is has been claimed that a neutrino would have a 50% chance of passing unhindered through a block of lead 50 light years thick! Vast numbers of neutrinos are created in the core of the Sun and other stars as a by-product of the energy-creating fusion reactions. The neutrinos zip through the Sun’s outer layers in just over a couple of seconds and escape into space. A small portion of them reach Earth just over eight minutes later. Detecting them gives us nearly instant news on what is going on inside the Sun. Neutrino astronomy is a small but important branch of our science.

In the now famous OPERA (Oscillation Project with Emulsion-tRacking Apparatus) experiment (which was actually intended to investigate the difference between sub-types of neutrino) the European scientists directed a beam of neutrinos through the Earth from CERN (European Centre for Nuclear Research) to the Gran Sasso Laboratory 730 km (453 miles) away in Italy. There the beam strikes a detector, composed of 150 000 bricks of alternating lead plates and photographic plates. If you divide the distance between those two points by the time it takes for the neutrinos to travel, you get their speed. It appears that the neutrinos arrived 0.000 000 06 seconds (60 nanoseconds) earlier than the 2.3 milliseconds taken by light. It is a tiny discrepancy, suggesting the neutrinos travelled at 1.000 02 times the speed of light but very disturbing to scientists. The researchers at OPERA have been careful to show that they have accounted for every conceivable source of error but almost certainly there is a problem with their experiment.

In 1987 we observed an exploding star, a supernova, in the Large Magellanic cloud. This cataclysmic event blasted out an abundance of neutrinos, easily detected here on Earth over 168 000 light years away. If neutrinos can travel faster than light, the neutrinos from Supernova 1987A would have got to Earth before the light of the explosion itself. If they travelled at the speed observed by the OPERA researchers, the neutrino detectors on Earth would have seen them four years before the supernova was visible. This did not happen; in fact the neutrinos from the supernova arrived three hours before the light! This does not mean the neutrinos outraced the supernova’s light, rather they had a head start. So dense is the core of an exploding star that it takes an appreciable time for the photons of light to force their way out and into space. This lag between the arrival of neutrinos and light from a supernova had been predicted in advance. This observational evidence is one strike against the results from CERN, but there is a deeper philosophical reason not to take them at face value.

A central tenet of modern science is the concept of “causality”, the idea that cause precedes effect. I spill a cup of hot coffee on to my lap and I yell out, the yell (effect) comes after the spill (cause), everyone who observes this minor disaster agrees on the sequence. So far so simple. However this is vital: causality is the philosophical glue which holds science and technology together. Imagine a machine, made of three subcomponents, A, B and C, which act in sequence to do a task at the press of a button. So I press the button, starting component A, A does its stuff, starts off B …all the way through to C and the desired outcome. How could such a thing be designed in a world without causality where C sometimes is activated before A, which happens before the button is pressed? If anything can move faster than the speed of light causality collapses and so does the whole, carefully-assembled edifice of science

What is more if FTL communications are possible, then it would be possible to observe a distant event occurring and transmit this information back to the site where it occurred before the event happened. What if the event is something important and the fore-knowledge prevents it? (“Don’t let the President go to Dallas!”)

Paradoxes like this are common in works of science fiction but are impossible to fit into a logical and consistent universe. FTL is functionally equivalent to time travel into the past, opening a horrendous can of worms. This is the deeper reason why FTL travel is impossible and why I am sceptical of this report from CERN. Please prove me wrong!

13 Comments

If it is true, then it helps me to understand Jehovah God’s foreknowledge, but if not…..I still believing about God’s foreknowledge, nothing is impossible for God to accomplish, he is the one that created and rules the laws of the phisical universe, that is easy to understand for those people with insight and depth of thought.

Aha, that old special relativity chestnut again. I think it was calculated that this could only account for a discrepancy of 2.3 +/- 0.9 ns. The other thing is that surely the level of scientific intelligence available at the CERN facility would have collectively finely sifted through every aspect of the timing mechanisms as this is the area where discrepancies are most likely to occur. Just a thought.

This does not completely explain or account for the time discrepancies, but does raise interesting questions about the way the OPERA team synchronised the times at both sites. Basically, the observed discrepancies are sub-GPS and must have been measured by (probably) an atomic clock that was transported between the two sites. This transportation through an accelerating frame of reference will cause a number of time distortions, an effect which may be further complicated by how the transportation was actually carried out (land vehicle, aircraft, continuous, discontinuous etc.). The writer also raises time dilation differences that may arise from the surface or aerial transportation of the clock when compared with the subterranean route taken by the neutrinos (in a gravitational field of a different strength).

I’m pretty happy with the idea of light speed being the universal speed limit and anything with mass not being abale to break the speed limit.

I’m also comfortable with the idea of tunalling, other dimentions or a bit of cable being a few meters to long to explain what was seen at cern.

What I don’t understand is how does breaking the speed limit infer the right to travel BACK in time.

In the example you have given,
If you are sitting at a target and viewed an event accuring at a source, there would be a lag of T based on the time it took for the event to travel to you assume it traveled at C.
You would then send a message to the source at say twice the speed of light, so there would be another delay 1/2T for your message to get to them.
I accept that the message would reach them before they would be able to see you send it, But I dont understand how you get the message there before the event occured.

Is this becaue the time dilation formula breaks down if you put in a velociy > c?

Sorry I just cant find anything which explains the leap from FTL = Travel back in time.

Hi Steve, thanks for your question. The idea that faster than light transmission leads to backwards time travel goes back to 1910 or so but was most famously articulated in the paper The Tachyonic Antitelephone by Benford, Book and Newcomb. It’s a tough read! Basically, it’s a consequence of special relativity, observers in different frames of reference observe time to move differently. if you have a faster than light communication link between A and B (B has to be moving very rapidly compared to A), A can send B a message, B responds and A hears the response before the original message was sent! It would be complicated to do in practise, but the very fact it can be considered scares physicists!

Do we understand enough about the mechanics of supernovae events to say that the initial neutrino and photon emissions are simultaneous? If, as you say, the explosion starts at the core, then the neutrinos will set off quite briskly at once – but is it a question of the following photons ‘forcing’ their way through the star before getting going themselves, or is it some form of shock wave propagating through the stellar structure which then causes photon emission from the surface? Or are these two scenarios effectively the same?

Hi David, I’ll be honest and say I’m not entirely sure. My understanding is that the photons “random walk” their way out of the core which is tearing itself apart at the same time – so it’s physically getting smaller and less dense, making it easier for them to escape.

I suppose you wouldn’t wear it if I were to say I read this article Yesterday. Thought not.

In the present time though, from what I have read around the web, the general concensus within the scientific community is one of total scepticism. Is this because it throws all existing science (eg relativity and the standard model) into doubt? And would require a total re-think of present theories.
I hope there is not a degree of arrogance creeping in that refuses to accept an event that goes beyond the mainstream, after all we readily admit that we do not fully understand the quantum world and such things as wave particle duality.
They will probably look to find the mass of the photon rather than invent the first warp drive. Well I can dream.
For what its worth I doubt that anything will come of it but if it did that would be one hell of a leap forward.
Things have become a bit static of late.

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